Aptitude - Problems on Ages - Discussion

I think (6x+10) means bringing the ages from past to present and then it was taken as present condition and +4 for the future age.

@ Faruk.

Good explanation.

Let us find the equation for 6 years ago.
x-6/y-6 = 6/5.
5(x-6)=6(y-6) ; 5x-30 = 6y-36 ; 5x-6y = -6-------- (1).

Let us find the equation for four years hence(later)
x+4/y+4 = 11/10.
10(x+4) = 11(y+4) ;10x+40 = 11y+44 ; 10x-11y= 4-------- (2)

Subtract eq (1)&(2).
10x-12y=-12 multiply by 2.
-10x+11y = -4.
----------------
Answer: y=16 Sagar present age.

I don't understand this problem. In this, we want to substract 6x-6?

Six year's ago that means we will do "_" ,why they adding+6 instead of -6?

Anybody help me.

It is clearly given that we have assumed the ages before six years and now we want the ages after 4 years of the present age. So we have to bring the ages to present age .so for that we have to add 6 to the ages that were before 6 years and we have to add 4 after that to calculate age after 5 years.

Ages before 6 years were 6x and 5x.
So present ages will be (6x+6)and (5x+6).
Ages after 4 years will be (6x+6)+4 and (5x+6)+ 4.

You are right @Pradnya.

I understand it now, thank you.

Data is insufficient. When It says 'n' years ago then It should be written like 'x-n' but not 'x+n'. Formula itself says '-' for n years ago.

In this question, why we add 4 to both numerator and denominator?

Guys, there is a shortcut for this method.

Let us take given options into consideration.

First, let's take option (a) that is 16 years (present age).

Given in the question that six years ago the ages of Kunal and Sagar is in the ratio (6:5) and we are asked to find the Sagar present age!

Hence 16-6 (six years ago) = 10.

10 is the multiple of 5 (Sagar age is 5x).

So condition one is satisfied.

In the next statement, they have given four years hence the ratio would be (11:10).

Meaning the Sagar's age is multiple of 10.

Hence (present age +four years).

We have taken option A into consideration that is 16.

So (16+4=20).

Which is a multiple of 10.

There you go both the conditions are satisfied and you have your answer.